scholarly journals Visual Exploration Area in Neglect: A New Analysis Method for Video-Oculography Data Based on Foveal Vision

2020 ◽  
Vol 13 ◽  
Author(s):  
Brigitte Charlotte Kaufmann ◽  
Samuel Elia Johannes Knobel ◽  
Tobias Nef ◽  
René Martin Müri ◽  
Dario Cazzoli ◽  
...  
Keyword(s):  
Visual Exploration ◽  
Analysis Method ◽  
Foveal Vision ◽  
Video Oculography ◽  
Exploration Area

scholarly journals Video-Oculography During Free Visual Exploration to Detect Right Spatial Neglect in Left-Hemispheric Stroke Patients With Aphasia: A Feasibility Study

2021 ◽  
Vol 15 ◽  
Author(s):  
Brigitte C. Kaufmann ◽  
Dario Cazzoli ◽  
Monica Koenig-Bruhin ◽  
René M. Müri ◽  
Tobias Nef ◽  
...  
Keyword(s):  
Spatial Neglect ◽  
Visual Exploration ◽  
Healthy Controls ◽  
Stroke Patients ◽  
Calibration And Validation ◽  
Video Oculography ◽  
Hemispheric Stroke ◽  
The Mean ◽  
Highly Correlated ◽  
Exploration Area

Spatial neglect has been shown to occur in 17–65% of patients after acute left-hemispheric stroke. One reason for this varying incidence values might be that left-hemispheric stroke is often accompanied by aphasia, which raises difficulties in assessing attention deficits with conventional neuropsychological tests entailing verbal instructions. Video-oculography during free visual exploration (FVE) requires only little understanding of simple non-verbal instruction and has been shown to be a sensitive and reliable tool to detect spatial neglect in patients with right-hemispheric stroke. In the present study, we aimed to investigate the feasibility of FVE to detect neglect in 10 left-hemispheric stroke patients with mild to severe aphasia as assessed by means of the Token Test, Boston Naming Test and Aachener Aphasie Test. The patient’s individual deviation between eye movement calibration and validation was recorded and compared to 20 age-matched healthy controls. Furthermore, typical FVE parameters such as the landing point of the first fixation, the mean gaze position (in ° of visual angle), the number and duration of visual fixations and the mean visual exploration area were compared between groups. In addition, to evaluate for neglect, the Bells cancellation test was performed and neglect severity in daily living was measured by means of the Catherine Bergego Scale (CBS). Our results showed that the deviation between calibration and validation did not differ between aphasia patients and healthy controls highlighting its feasibility. Furthermore, FVE revealed the typical neglect pattern with a significant leftward shift in visual exploration bahaviour, which highly correlated with neglect severity as assessed with CBS. The present study provides evidence that FVE has the potential to be used as a neglect screening tool in left-hemispheric stroke patients with aphasia in which compliance with verbal test instructions may be compromised by language deficits.

scholarly journals Test-Retest-Reliability of Video-Oculography During Free Visual Exploration in Right-Hemispheric Stroke Patients With Neglect

2020 ◽  
Vol 14 ◽  
Author(s):  
Brigitte Charlotte Kaufmann ◽  
Dario Cazzoli ◽  
René Martin Müri ◽  
Tobias Nef ◽  
Thomas Nyffeler
Keyword(s):  
Visual Exploration ◽  
Stroke Patients ◽  
Retest Reliability ◽  
Video Oculography ◽  
Hemispheric Stroke ◽  
Test Retest Reliability

scholarly journals Foveal vision at the time of microsaccades

2021 ◽  
Author(s):  
Naghmeh Mostofi ◽  
Janis Intoy ◽  
Michele Rucci
Keyword(s):  
Eye Movements ◽  
Contrast Sensitivity ◽  
Time Course ◽  
Visual Sensitivity ◽  
Saccadic Suppression ◽  
Visual Exploration ◽  
Social Grooming ◽  
Foveal Vision ◽  
High Acuity ◽  
Display Control

AbstractHumans use rapid eye movements (saccades) to inspect stimuli with the foveola, the region of the retina where receptors are most densely packed. It is well established that visual sensitivity is generally attenuated during these movements, a phenomenon known as saccadic suppression. This effect is commonly studied with large, often peripheral, stimuli presented during instructed saccades. However, little is known about how saccades modulate the foveola and how the resulting dynamics unfold during natural visual exploration. Here we measured the foveal dynamics of saccadic suppression in a naturalistic high-acuity task, a task designed after primate’s social grooming, which—like most explorations of fine patterns—primarily elicits minute saccades (microsaccades). Leveraging on recent advances in gaze-contingent display control, we were able to systematically map the peri-saccadic time-course of sensitivity across the foveola. We show that contrast sensitivity is not uniform across this region and that both the extent and dynamics of saccadic suppression vary within the foveola. Suppression is stronger and faster in the most central portion, where sensitivity is generally higher and selectively rebounds at the onset of a new fixation. These results shed new light on the modulations experienced by foveal vision during the saccade-fixation cycle and explain some of the benefits of microsaccades.

scholarly journals A quantitative analysis method for comitant exotropia using video-oculography with alternate cover

2018 ◽  
Vol 18 (1) ◽  
Author(s):  
Nohae Park ◽  
Byunggun Park ◽  
Minkyung Oh ◽  
Sunghyuk Moon ◽  
Myungmi Kim
Keyword(s):  
Quantitative Analysis ◽  
Analysis Method ◽  
Video Oculography ◽  
Quantitative Analysis Method

scholarly journals Comparison of Methods for Determining the Thresholds of Geochemical Anomalies and the Prospecting Direction—A Case of Gold Deposits in the Gouli Exploration Area, Qinghai Province

Minerals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 368 ◽  
Author(s):  
Dingjie Chen ◽  
Junhao Wei ◽  
Wenhui Wang ◽  
Wenjie Shi ◽  
Huan Li ◽  
...  
Keyword(s):  
Principal Component ◽  
Singularity Analysis ◽  
Cumulative Frequency ◽  
Analysis Method ◽  
Robust Principal Component Analysis ◽  
Frequency Method ◽  
Qinghai Province ◽  
Geochemical Anomalies ◽  
Local Singularity ◽  
Exploration Area

Geochemical anomalies play an important role in mineral exploration, because they are closely related to the formation of ore deposits. In this paper, the Au in the geochemical samples of 1:50,000 stream sediments in the Gouli exploration area, Qinghai Province, is selected as an example. The cumulative frequency method, local singularity analysis, and exploration data analysis method are used to process the Au data and determine the abnormal thresholds. Robust principal component analysis is used to explore the elemental associations. Among them, the effect of local singularity analysis is the best and it delineates the weak geochemical anomalies not delineated by cumulative frequency method and exploration data analysis method, which shows its superiority. Robust principal component analysis shows that Sb, W, and As are closely related to Au mineralization. Three anomalous areas are delineated in the Gouli exploration area. Gold ore-body is found to occur within anomaly area I. The other anomalous areas are highly consistent with abnormal elemental composition of Sb, W, and As. Moreover, these two areas are extremely conformable with the high-value areas determined by the binary state method. The optimality of the three methods are compared comprehensively, it is pointed out that it is more reasonable to use the local singularity analysis to determine the abnormal threshold. The anomaly areas II and III of Au determined by local singularity analysis have shown great potential for prospecting.

scholarly journals Fast and nonuniform dynamics of perisaccadic vision in the central fovea

2021 ◽  
Vol 118 (37) ◽  
pp. e2101259118
Author(s):  
Janis Intoy ◽  
Naghmeh Mostofi ◽  
Michele Rucci
Keyword(s):  
Time Course ◽  
Visual Sensitivity ◽  
Saccadic Suppression ◽  
Visual Exploration ◽  
Social Grooming ◽  
Foveal Vision ◽  
High Acuity ◽  
Display Control ◽  
Shed Light ◽  
Central Fovea

Humans use rapid eye movements (saccades) to inspect stimuli with the foveola, the region of the retina where receptors are most densely packed. It is well established that visual sensitivity is generally attenuated during these movements, a phenomenon known as saccadic suppression. This effect is commonly studied with large, often peripheral, stimuli presented during instructed saccades. However, little is known about how saccades modulate the foveola and how the resulting dynamics unfold during natural visual exploration. Here we measured the foveal dynamics of saccadic suppression in a naturalistic high-acuity task, a task designed after primates’ social grooming, which—like most explorations of fine patterns—primarily elicits minute saccades (microsaccades). Leveraging on recent advances in gaze-contingent display control, we were able to systematically map the perisaccadic time course of sensitivity across the foveola. We show that contrast sensitivity is not uniform across this region and that both the extent and dynamics of saccadic suppression vary within the foveola. Suppression is stronger and faster in the most central portion, where sensitivity is generally higher and selectively rebounds at the onset of a new fixation. These results shed light on the modulations experienced by foveal vision during the saccade-fixation cycle and explain some of the benefits of microsaccades.

The Gender Typicality of Faces and Its Impact on Visual Processing and on Hiring Decisions

2013 ◽  
Vol 60 (6) ◽  
pp. 444-452 ◽  
Author(s):  
Lisa von Stockhausen ◽  
Sara Koeser ◽  
Sabine Sczesny
Keyword(s):  
Visual Processing ◽  
Past Research ◽  
Visual Exploration ◽  
Facial Appearance ◽  
Leadership Roles ◽  
Hiring Decisions ◽  
Leadership Selection ◽  
Gender Typicality ◽  
Second Stage ◽  
The Feminine

Past research has shown that the gender typicality of applicants’ faces affects leadership selection irrespective of a candidate’s gender: A masculine facial appearance is congruent with masculine-typed leadership roles, thus masculine-looking applicants are hired more certainly than feminine-looking ones. In the present study, we extended this line of research by investigating hiring decisions for both masculine- and feminine-typed professional roles. Furthermore, we used eye tracking to examine the visual exploration of applicants’ portraits. Our results indicate that masculine-looking applicants were favored for the masculine-typed role (leader) and feminine-looking applicants for the feminine-typed role (team member). Eye movement patterns showed that information about gender category and facial appearance was integrated during first fixations of the portraits. Hiring decisions, however, were not based on this initial analysis, but occurred at a second stage, when the portrait was viewed in the context of considering the applicant for a specific job.

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